Culling method for blister-pack production line

ABSTRACT

A continuous and elongated blister-pack strip having transverse rows of blisters of which some are empty and most are full is transported through a stamping station. Upstream of the stamping station whether any blisters entering the stamping station are full or empty is sensed. In the stamping station only sections all of whose blisters are full are stamped out of the strip from between the edges thereof while leaving the edges flanking the stamped-out section intact so that sections of the strip having at least one empty blister leave the stamping station attached to the strip edges. The stamped-out sections are transported away from the path at the stamping station. Spaces in the strip between blisters still attached to the strip edges are then detected and the entire strip is transversely cut only between the respective blisters into pieces each including at least one row of intact blisters.

CROSS REFERENCE TO RELATED APPLICATION

This application is a division of copending application Ser. No.10/975,924 filed 28 Oct. 2004.

FIELD OF THE INVENTION

The present invention relates to a blister-pack production line. Moreparticularly this invention concerns a method of culling out defectivepackages from such a line.

BACKGROUND OF THE INVENTION

It is standard to package small items, e.g. pills, in blister packs sothat the contents of each blister are visible but hermetically sealedand well protected. Thus a standard blister-pack production linehorizontally advances a lower foil formed with upwardly open pockets orblisters arrayed in transversely extending rows separated bytransversely extending spaces. Each blister is loaded with one or apredetermined number of the objects being packed, then another foil isapplied to the top face of the lower foil and the two foils are bondedtogether all around the blisters. Subsequently the two bonded foils,which normally move either continuously or in steps, pass through astamping station where sections normally including a predeterminednumber of the blisters are punched out and passed on for furtherpackaging.

Typically one or both of the foils is transparent and means such asdescribed in German 42 43 206 of J. Oehlmann or 195 05 256 of U.Zietmann is used to verify that each blister is properly filled. It isextremely important that packages not be sent out with overloaded,underloaded, or empty blisters, especially as these blister packs areoften used to ensure regular consumption of critical medications.

German 199 17 436 of A. Weinert et al describes such an arrangement inwhich immediately upstream of the stamping station where the continuousstrip is subdivided into sections there is a monitoring station thatscans the passing filled and bonded strip and that can distinguishbetween properly filled blisters and improperly filled ones. When asection is detected that is only partially filled, it is stamped out ofthe strip like the good sections but is subsequently routed off. When asection is detected that is completely empty, it is not stamped out butis left hanging on the strip for later chopping and use as regrind.

These systems are all fairly complex. They do not adequately segregatethe unusable partially filled or empty sections from the good sectionsand from each other. Thus the culls can get back into the productionline. Furthermore the culls themselves require considerable attention sothat, for instance, valuable or dangerous medicaments are not choppedup.

OBJECTS OF THE INVENTION

It is therefore an object of the present invention to provide animproved culling method for a blister-pack production line.

Another object is the provision of such an improved culling method for ablister-pack production line that overcomes the above-givendisadvantages, in particular that is simple, and that accuratelyseparates filled usable strip sections, partially filled sections, andempty sections from one another.

SUMMARY OF THE INVENTION

A continuous and elongated blister-pack strip having transverse rows ofblisters of which some are empty and most are full is transportedthrough a stamping station. An upstream sensor along the path upstreamof the station determines whether the blisters entering the station arefull. A device in the station stamps out of the strip sections eachincluding a plurality of blisters. A controller connected between theupstream sensor and the stamper for inhibits action of the stamper andthereby leaves unfilled blisters on the strip when any blisters in thestation are not full. A conveyor transports the stamped-out sectionsaway from the path at the station. A downstream sensor along the pathdownstream of the station detects spaces in the strip between anyblisters left on the strip, and a cutter along the path downstream ofand connected to the downstream sensor severs the strip between the rowsof blisters into pieces each including at least one row of intactblisters.

Thus with this system the stamper only separates out perfect sections ofthe strip, that is sections all of whose blisters have the desirednumber of objects. If one blister is empty or overfilled, or even if itis improperly glued or has some other defect, the respective section isleft on the strip. Then according to the invention the strip is cut intopieces between the rows of blisters so that the contents of any fullblisters are not damaged. Since the strip remains continuous, with atworst holes where good sections have been punched out, it is extremelyeasy to handle.

According to the invention the downstream sensor also detects whetherthe blisters passing it are full or empty. The system further hasaccording to the invention a deflector downstream of the cutter forseparating the pieces all of whose blisters are empty from the piecessome of whose blisters are filled. The cut-off pieces that arecompletely empty can be chopped up and reused, for example, as regrind,or discarded. The more difficult to dispose of pieces holding productcan be handled differently, for example the contents can be recovered orthey can be treated as dangerous waste.

The cutter according to the invention includes a fixed blade to one sideof the path and a rotating blade to an opposite side of the path. Therotating blade turns about an axis transverse to a direction of movementof the strip along the path. Its rotation is synchronized with theadvance of the strip, something that is fairly easy as the strip is leftcontinuous and quite easy to handle.

The upstream sensor in accordance with the invention includes a camera.The downstream sensor is normally a more simple light curtain that canalso be set up to detect, when the foils making up the strip aretransparent, whether any blisters of a given row are full.

The conveyor includes a suction lifter for picking the stamped-outsections out of the stamping station and a conveyor belt adapted toreceive the stamped-out sections from the suction lifter and transportthem from the station. Another sensor can be juxtaposed with theconveyor belt for detecting the stamped-out sections thereon.

BRIEF DESCRIPTION OF THE DRAWING

The above and other objects, features, and advantages will become morereadily apparent from the following description, reference being made tothe accompanying drawing in which:

FIGS. 1 and 2 are partly schematic side views illustrating the system ofthis invention;

FIG. 3 is a perspective view of the system; and

FIG. 4 is a perspective view illustrating the package strip.

SPECIFIC DESCRIPTION

As seen in the drawing a strip 4 is moved in a transport direction Dalong a path through a stamping station 1 and comprises a lower foilformed with blisters 8 most of which are filled and an upper foil bondedover the lower foil. The blisters 8 are arrayed in six-abreast rowsextending perpendicular to the direction D with gaps between adjacentrows where there is nothing but the thickness of the two foils formingthe strip 4.

The stamping station 1 is provided with a device 5 that is capable ofcutting from between the edges of the strip 4 a section 2 (see FIG. 4)here shown to have four rows of blisters 8, for a total of 24 blisters8. A suction-type gripper 9 can pick up the stamped out sections 2 anddeliver them to a conveyor belt 6 that carries them off, with thesections 2 hanging from the lower reach of this conveyor 6, for exampleheld thereon by vacuum or an unillustrated pair of lower belts, past asensor station 10 that verifies the passage of the sections 2.

A camera-type sensor 7 upstream of the stamping station 1 is connectedto a controller 17 that only operates the device 5 when all of theblisters 8 in the section 2 to be stamped out are properly filled, thatis each blister 8 has the desired number—normally one—of objects. Thusaccording to the invention if a section 3 (FIG. 4) has one or more emptyblisters 8, it is not stamped out of the strip 4, but instead is left onit, and in fact the strip 4 is left as two continuous edge bands wherethe sections 2 have been punched out, so that it remains extremely easyto handle and guide.

Downstream of the station 1 the strip 4 passes between a pair of belts18 that feed it past a light-curtain sensor 15 formed as a simplephotocell and lamp directed transversely across the path of the strip 4and serving to distinguish between regions of the strip 4 with blisters8 and those without. This sensor 15 is connected via the controller 17with a cutter 12 comprised of a stationary blade 14 and a rotary blade13. The blade 13 is spun by a motor 19 operated by the controller 17 soas to cut the strip 4 between rows of blisters 8. Thus the cutter 12will not indiscriminately chop up the strip with its full and emptyblisters 8, but will chop it into transverse strips each holding one ormore rows blisters 8. Never will a blister 8 be cut.

In fact the sensor 15 is also capable of determining whether any of theblisters 8 in a given row or in a passing cull section 3 is full and adeflector 16 downstream of the cutter 12 is operated by the controller17 to deflect the chopped-off rows of blisters 8 from the strip 4 intoeither a passage 20 for completely empty blisters, or a passage 21 forrows having at least one full blister. The completely empty blisters canbe simply chopped up and recycled as regrind. The partially fullblisters can be emptied of their contents and then comminuted, orotherwise handled.

1. A method of making blister-pack packages, the method comprising thesteps of: displacing along a longitudinal path through an upstreamdetecting station, a stamping station downstream of the upstreamstation, and a downstream detecting station downstream of the stampingstation a continuous longitudinally elongated blister-pack strip havingtransverse rows of blisters of which some are empty and most are full,the rows of blisters being flanked by longitudinal edges of the strip;sensing at the upstream detecting station whether any blisters enteringthe stamping station are full or empty; in the stamping station stampingout of the strip from between the edges thereof only sections all ofwhose blisters are full while leaving the edges flanking the stamped-outsection intact so that sections of the strip having at least one emptyblister leave the stamping station attached to the strip edges;transporting the stamped-out sections away from the path at the stampingstation; and detecting in the downstream detecting station spaces in thestrip between blisters still attached to the strip edges and theretransversely cutting the entire strip only between the respectiveblisters into pieces each including at least one row of intact blisters.2. The packaging method defined in claim 1 wherein the stamped-outsections are transported away from the path at the stamping station bymeans of a suction lifter that picks the stamped-out sections up out ofthe stamping station.
 3. The packaging method defined in claim 1,further comprising the step of at a second detecting station downstreamof the first downstream detecting station detecting station detectingwhether the blisters passing are full or empty; and there separating anypieces all of whose blisters are empty from the pieces some of whoseblisters are filled.
 4. The packaging method defined in claim 3, furthercomprising the step of transporting the separated pieces away from thepath.
 5. The packaging method defined in claim 1 wherein pieces aretransported away by a conveyor belt
 6. The packaging method defined inclaim 5, further comprising the step of continuously operating theconveyor belt and detecting the stamped-out sections thereon.
 7. Thepackaging method defined in claim 1 wherein the pieces each include onlyone row of blisters.